#include <conio.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(){
	char*str;

	str = (char*) calloc(20,sizeof(char));
	
	printf("Nhap xau: ");
	gets(str);
	int j = strlen(str) - 1;
	int i = 0;
	while(i <= j){
		char ch  = str [i];
		str[i ] = str[j];
		str[j] = ch;
		j--;
		i++;
		
	}
	puts(str);
	getch(); 
}
